Transmission of data via radio signals is an effective means of promoting communication between a variety of devices located within range of a radio signal transmitter. An advertiser, or other provider of data (including content) may pre-select a radio frequency carrier type (e.g. FM sub-carrier, AM sub-carrier, cellular, etc.) a broadcasting station (e.g. KIIS FM), and/or a frequency over which the data will be broadcast (e.g. 102.7 MHz @ 57 kHz RBDS) based on the geographic location of the target audience. The particular frequency may be chosen because of its popularity with the target audience, its spectrum availability, the type of device that is intended to receive the signals and, most importantly, because that particular transmitter's signals exhibit a large footprint (i.e., is able to cover or reach a large targeted audience).
Covering the target audience is deemed essential, but since many applications of radio frequency (RF) communications target an audience existing within a relatively small geographic area, target audience coverage is often not considered a problem. For example, it is common to broadcast music or news over a pre-selected frequency to all areas of an office building. Pre-selection of the frequency and pre-tuning of the receivers to that frequency is a relatively simple process. Another example of an RF communication within a relatively small area is a radio controlled model that is set to receive signals broadcast over a pre-selected frequency. Yet another example of selected target audience coverage is discussed in U.S. Pat. No. 6,298,218 to Lowe et al. which is directed to target audiences within a few feet of the transmitting device. The disclosure of the '218 patent is exemplified by an athletic club environment in which a user device receives different broadcasts on different frequencies depending on the user's proximity to specific pieces of gym equipment having embedded transmitters.
Thus, those applications that target audiences over a relatively small area typically work well with pre-selection of frequency and transmission station. Coverage becomes an issue and complications arise, however, when the target audience is spread over an area that encompasses more than one frequency, transmission station, and/or frequency band. These complications are due in part to the necessity to pre-select many, perhaps hundreds or thousands, of frequencies and stations in order to cover the entire target audience. Thus, pre-selection of frequencies becomes extremely burdensome when a widespread audience has been targeted.
And even further difficulty arises when it is understood that certain communication applications might be intended for use within specific geographic locations and whose use might be absolutely precluded outside of those locations. For example, an RF enabled gaming device might allow user to participate in a gambling activity, in conjunction with a broadcast gaming opportunity from a casino, for example. Since gaming is often a highly regulated activity and its participation is strictly limited to specific regions within a state or within specific states, any RF enabled gaming communication methodology must be able to differentiate between authorized and unauthorized participation. In summary, target audience coverage is not so much the issue as the physical location of each member of the target audience within a broadcast footprint.
By way of example, gaming is authorized within certain designated locations in the State of California (Native American Reservation Gaming, for example), while stringently controlled elsewhere. These locations have distinct and well defined boundaries, such that gaming might be authorized for a user standing in one spot, while criminally penalized for a user standing only a few feet away. Similarly, the boarder between the states of Nevada and Utah is equally sharp; a user on the Nevada side being authorized to participate in gaming activities, a user on the Utah side being penalized for such participation.
Accordingly, there is a need for systems and methods which facilitate the use of the RF transmission spectrum to communicate with RF enabled devices that may be spread over a relatively large area and, depending upon the form of content communicated to such devices, be able to differentiate the physical location of such devices within the relatively large area.